\Pro-\ [L. pro, or Gr. ?. See {Pro}.]
A prefix signifying before, in front, forth, for, in behalf
of, in place of, according to; as, propose, to place before;
proceed, to go before or forward; project, to throw forward;
prologue, part spoken before (the main piece); propel,
prognathous; provide, to look out for; pronoun, a word
instead of a noun; proconsul, a person acting in place of a
consul; proportion, arrangement according to parts.

\Pro\, prep. [L.; akin to prae before, Gr. ?, and E. for.
See {For}, prep., and cf. {Prior}, a.]
A Latin preposition signifying for, before, forth.
{Pro confesso} [L.] (Law), taken as confessed. The action of
a court of equity on that portion of the pleading in a
particular case which the pleading on the other side does
not deny.
{Pro rata}. [L. See {Prorate}.] In proportion; proportion.
{Pro re nata} [L.] (Law), for the existing occasion; as
matters are.

\Pro\, adv.
For, on, or in behalf of, the affirmative side; -- in
contrast with {con}.
{Pro and con}, for and against, on the affirmative and on the
negative side; as, they debated the question pro and con;
-- formerly used also as a verb.
{Pros and cons}, the arguments or reasons on either side.